© APAnwar al-Awlaki, a US citizen, was killed in an American drone strike in Yemen.
The families of the three - including Anwar al-Awlaki, a New Mexico-born militant Muslim cleric who had joined al-Qaida's Yemen affiliate, as well as his teenage son - sued over their 2011 deaths in US drone strikes, arguing that the killings were illegal.
Judge Rosemary Collyer of the US district court in Washington threw out the case, which had named as defendants the former defence secretary and CIA chief Leon Panetta, the former senior military commander and CIA chief David Petraeus and two other top military commanders.
"The question presented is whether federal officials can be held personally liable for their roles in drone strikes abroad that target and kill U.S. citizens," Collyer said in her opinion. "The question raises fundamental issues regarding constitutional principles and it is not easy to answer."
But the judge said she would grant the government's motion to dismiss the case.
Collyer said the officials named as defendants "must be trusted and expected to act in accordance with the US constitution when they intentionally target a US citizen abroad at the direction of the president and with the concurrence of Congress. They cannot be held personally responsible in monetary damages for conducting war."
Awlaki's US-born son Abdulrahman al-Awlaki was 16 years old when he was killed. Also killed was Samir Khan, a naturalised US citizen who had moved to Yemen in 2009 and worked on Inspire, an English-language al-Qaida magazine.
The American Civil Liberties Union and the Centre for Constitutional Rights, both based in New York, represented the families. They had argued that in killing American citizens the government violated fundamental rights under the US constitution to due process and to be free from unreasonable seizure.
"This is a deeply troubling decision that treats the government's allegations as proof while refusing to allow those allegations to be tested in court," said ACLU lawyer Hina Shamsi. "The court's view that it cannot provide a remedy for extrajudicial killings when the government claims to be at war, even far from any battlefield, is profoundly at odds with the Constitution."
Centre for Constitutional Rights lawyer Maria LaHood said the judge "effectively convicted" Anwar al-Awlaki "posthumously based solely on the government's say-so". LaHood said the judge also found that the constitutional rights of the son and of Khan "weren't violated because the government didn't target them".
"It seems there's no remedy if the government intended to kill you, and no remedy if it didn't. This decision is a true travesty of justice for our constitutional democracy and for all victims of the US government's unlawful killings," LaHood said.
Collyer ruled that the families did not have a claim under the Constitution's fourth amendment guarantee against unreasonable seizures because the government did not seize or restrain the three who were killed. "Unmanned drones are functionally incapable of 'seizing' a person; they are designed to kill, not capture," she wrote.
Collyer wrote that the families had presented a plausible claim that the government violated Awlaki's due process rights. "Nonetheless the court finds no available remedy under US law for this claim," the judge wrote.
"In this delicate area of war making national security and foreign relations the judiciary has an exceedingly limited role."
Allowing claims against individual federal officials in this case "would impermissibly draw the court into the heart of executive and military planning and deliberation", she wrote. It would "require the court to examine national security policy and the military chain of command as well as operational combat decisions".
Nasser al-Awlaki, father of Anwar al-Awlaki, said he was disappointed in the American justice system and "like any parent or grandparent would, I want answers from the government when it decides to take life, but all I have got so far is secrecy and a refusal even to explain".
Drone attacks have killed several suspected figures in al-Qaida's Yemen-based affiliate including Awlaki, who is accused of orchestrating plots to bomb a Detroit-bound airliner in 2009 and US cargo planes in 2010.
The United States has faced international criticism for its use of drones to attack militants in places such as Pakistan and Yemen. A UN human rights watchdog in March called on the Obama administration to limit its use of drones targeting suspected al-Qaida and Taliban militants.
Barack Obama's administration increased the number of drone strikes after he took office in 2009 but attacks have dropped off in the past year. The US has come under pressure from critics to rein in the missile strikes and do more to protect civilians.
No war was declared and a US citizen was targeted for murder. Better yet, hang the judge along with the people responsible.